import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 高生平
 * Date: 2025-09-06
 * Time: 19:21
 */
public class Test {
    public static int fib (int n) {
        if (n == 1) {
            return 0;
        }
        if (n == 2) {
            return 1;
        }
        return fib(n - 1) + fib (n - 2);
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();;
        System.out.println("斐波那契数列的第" + n + "项为：" + fib(n)) ;
    }
}
